An example of the conventional user authentication method and system is disclosed in Patent document 1. As shown in FIG. 17, the conventional user authentication system includes a user terminal 110 (portable communication device) having a sensor (image sensor) 111 that is a biometric information input means, a registered biometric information database (DB) 112 that stores registered biometric information, and a collation unit 113 that compares two pieces of biometric information, and a service provider device 120 (central processing unit) that communicates with the user terminal 110 through the Internet and deals a financial transaction and the like based on the determination of a service provision possibility determination unit 121.
The conventional user authentication system provided with this configuration is operated as follows. That is a user who is to receive a service makes a sensor read in biometric information, and the biometric information thus read in is compared with registered biometric information which has been stored in the previously registered biometric information database (DB) 112 in the collation unit 113, and the authentication result is sent to the service provider device 120 through the Internet. When it is determined that the two pieces of biometric information accord with each other by the comparison authentication, the service provider device receives information that the authentication is ended from the user terminal 110, and the service provision possibility determination unit 121 of the service provider determines whether or not a service is provided. Patent Document 1: JP-A 2002-033823